Pressure fixing of toners

ABSTRACT

A method of fixing toners to a surface without the use of heat employs pressure which is applied by two somewhat compliant rolls, or one somewhat compliant roll and one relatively rigid roll. The use of such an arrangement makes it possible to apply a substantially uniform pressure to the toned areas to secure a uniform fixing action throughout.

-- United States Bren'nema'n et 31.

Patent 11 1 1111 3,854,975 1 Dec. 17, 1974 PRESSURE FIXING OFTONERS 54] 3,338,735 8/1967 Hain., 117/65.2 ,011 8 1968 N l. l 4 [75] Inventors: Richard S. Brenneman, Natlck; 548 341969 ggg i g David W-LWeriPgmeedham, both 3,345,937 10/1967 Kusters etal. 29/132 of Mass; FrederlckE- Barr, 3,511,729 5 1970 Williams 29 132 Vermillion, 01110 3,637,416 l/l972 MlSCh Et al. 29/132 i 3,753,276 8/1973 Reisch... 29/132 [73] AddWSSQFPaPh'MMt'E'aP" 1,055,404 3/1913 Kremmerm. 118/117 9 w! Cleveland, Q1110 2,71 1,985 6/1955 Olson 117/21 22 Filed: Mar. 12 1973 2,852,412 9/1958 Hassellu... 118/114 2,859,673 11/1958 Hix et a1. 117/17.5 [21] Appl. No.1 340,600 2,955,052 10/1960 Carlson et al 1,17/21 3,013,526 12/1961 Crumrin'e et al.... ll7/17.5 Related PP Data 3,063,859 11/1962 Heckscher 117/17 5 [63] Continuation-impart of Ser'. No. 51,089, June 30, 3,071,070 /1 Matthews et 7 1971, abandoned, which is a continuation of Ser. No. 1 3, 1 6/1963 clundlach 6t 5 694,515, Dec. 29, 1967, abandoned, 3,094,429 6/1963 1-10we11 117/17 5 v 1 3,268,351 8/1966 Van Dorn..... 117/21 [52] 11.8. C1 117/21, 29/132, 11l7/l7.5, I

/1 Primary Examiner-Michael 'Sofocleous [51] In t. Cl. G03g 13/20, G03g 15/20 I I 3 [58] Field of Search 117/9, 16, 17.5, 2l;-

113/114, 116, 117, 637; 21'9/216,'388, 469, 1 7 BS C 1' 470; 2 181; 29/132' A method of fixing toners to a surface without the use g 1 of heat employs; pressure which is applied by two 6 References C'ted somewhat compliant rolls, or one somewhat compliant UNITED STATES E roll and one relatively rigid roll. The use of such an 3.501.823 3/1970 Gregersen et al 29/132 arrangement makes Possible to pp y a Substantially 3,617,445 11/1971 Brafford 162/358 'uniform pressure: to the to'ned'areas to secure a uni- 3,269,626 8/1966 Albrecht 226/177 form fixing 3611011 throughout. 3,307,993 3/1967 Gottwald et al. l17/65.2 V 3,331,592 7/1967 Cassano et al 219/388 21 Claims, 3 Drawing-Figures a 05145101 5? M WIT/0N 1 /5 1 1 l vA? TRANSFER pmgmgunanmsu' D 3, 54,975 I sum 2 9 2 I JNVENTORS. RICHARD S, BRENNEMAN DAVID W. LOVERING FREDERICK EBARR BY f3:-

. AT TDRNE Y Ser. No. 694,515, filed-Dec. 29, I967 now abandoned.

7 STATEMENT OF BACKGROUND AND OBJECTS The process of copying indicia by the technique of forming an electroscopic powder on a surface of a substrate material is well developed. Typically, this is accomplished in either of two ways. In either of these methods, a photoconductive surface is electrically charged and then exposed to a lightandshadow pattern of the image. The electrostaticcharge which was 'deposited upon the photoconductive surface is removed from thoseplaces exposed to light, leaving a latent electrostatic image which can be developed. Develop-.

ment is accomplished by exposing the electrostatic image toa colored powder, usuallyreferred to as a toner in this context, having the property of being to properly fix the toner, it is necessary to apply excessive pressures to the high points. This, in turn, can ma- 'terially alter the substrate and bring about unwanted attractedto the electrostatic image-areas. According to the first method, the toner is then fixed (permanently adhered) to the photoconductive surface. According to the other method the toner image formed on the photoconductive layer is first transferred to another substrate, e.g.,. a sheet of ordinary paper, and is then fixed I on that other substrate.

"carbon black'or other pigment, and a small amount of dye. The exact composition depends upon the specific purpose for whichit is to be usedfl The fixing or adhering of the toner is normally ac complished by'heat'fusing the thermoplastic resin component thereof. This is'usually performed by exposng theimage to heat for a time sufficient to melt somewhat the toner particles so that they adhere, one to the other,

and to the paper or substrate. Some fixing techniques have also employed the pressure developed by two suface characteristics in the unprinted areas, ile.. make certain areas shiny or glossy rather than permitting them to remain dull, and in any event almost certainly fails to provide degrees of'fixing in'various portions of the sheet'which are sufficiently uniform to be practical in most applications.

It is perhaps theoreticallypossible, if the destructive effect upon the sheet could be neglected, to urge the rollers together with sufficient force to provide general and fairly uniform fixing of the toner on a sheet of ordinary size, for example 8% inches by l 1 inches. The difficulty, however, is, that the loading required in such a situation may well transcend thenormal range by such a large amount that the mechanical elements of the system (such as the rollers themselves and their loadapplying bearings) would either fail directly under the applied load, or would deteriorate so rapidly due to fatigue that no practical device could be constructed to accomplish this end within the framework of normal economic. realities. v v

It-is therefore a primary object of this invention to provide an improved method for pressure fixing toners .to a substrate without the .use of heat. It is anotherobject to provide a method which supplies a substantially uniform pressure to the toned areas without adversely affecting portions of the substrate. It is another object of the invention to provide an arrangement or narrow band, progressive contact, pressure members for pressure fixing a toner to'a substrate, which pressure members have properties such thatthey can produce an efhard surfacedrolls to'fix the particles. Another proposed process passes the substrate between hard Surfaced rolls in combination with the appli'cation of heat. 7 Heat fusing while producing effective results in many cases, is'undesirable in that it requires that a supply of' heat beavailable, usually entailing a supply of electricpower in large quantities, and presents the possibility of overheating the substrate as well as the toner, with some danger of fire as a result. Pressure fixing as applied in the prior art has consisted of passing the toned substrate between two hard surfaced rolls, formed of metal, one roll being movable and connected with springs to provide a controlled pressure. (See for example US. Pat. No. 3,269,626). Experience has shownthat this type of pressure fixing proves very un- -Under high loadings the character of the paper substrate itself may be materially altered, for to apply enough pressure to the low points or areas in the paper fective uniform fixing action ona substrate sheet of normal size underreasonable loading forces, thus per-- form, the appara'tusfor accomplishing the customary I precedent steps of charging, exposing, developing, and

in some cases transferring;

FIG. 2 is an enlarged side elevation of the pressure fixing portion of the apparatus shown in FIG. 1 loading and driving means omitted; and

FIG. 3 is a diagrammatic side elevation to a larger scale showing cylinders in relaxed engagement and in pressure engagement, and illustrating the meaning of certain symbols used in the description.

DESCRIPTION OF THE PREFERRED with the EMBODIMENT Y Referring to FIG. 1, the process of forming the pow der image is carried out in the usual manner wherein a member or sheet carrying a photoconductive layer is automatically fed past a charger 3 to receive auniform static charge on its surface, is then automatically fed to an exposure station 4 where it is exposed to a light and shadow pattern corresponding to the desired image,

then is automatically fed to developer equipment 5 where the latent image is developed with a ton'erpowder according to known procedures and finally fed directly (as by path 6) to a fixing station 10. In the alternative. a latent electrnstatir-imnon similar-Iv fm-mnd nn the photoconductive layer of a member or sheet may be developed with toner, and the toner image thus formed transferred therefrom to another sheet or substrate as both are fed automatically (as'by alternate path 7) through a transfer station 8. In any event, the resulting product is a flexible sheet or substrate 11 with a loosely held image 13 defined by toner powder on its surface, being automatically fed to a fixing station 10. In accordance with the invention herein the substrate carrying the toner image is then passed through the said fixing station which comprises pressure members which progressively contact'each other along a line of narrow band area, and emerges with the image consolidated and firmly adhered to the substrate as at 13'.

Normally, these pressure members consist of a roll and an opposing member in rolling pressure contact therewith. In the most convenient arrangement, this opposing member is also a roll.

In the preferred form illustrated in the drawing there are two rolls I5 and 17 forming a nip into which the toner bearing sheetll is passed. In accordance with prior practice these rolls would be hard metal rolls, but.

in accordance with the present invention it has been discovered that at least one of these rolls or members should be of softer, more compliant material. From a basic fixing standpoint, both members or rolls could be 7 equally compliant or deformable. However, from the standpoint of effective practical operation, it-is found that it isusually easier to provide a toner rejecting surface on a hard, relatively rigid, member. Accordingly, the upper'roll 15 in contact with the toner image is preferably a hard surfaced metal roll, and the lower roll l7 is of a softer and more compliant material.

types of such resilient rolls are known in the papermaking art for various purposed unrelated to the instant problem. The form of compliant roll presently preferred is one which is made up of stacked sheets of textile embodying cotton fibers and wool fibers in approximately equal amounts. The more compliant roll must generally has a central metal shaft (e.g., steel) covered with a layer of the more compliant material, which layer is usually effectivefor the purposes of the invention when the thickness of the layer is one-fourth or more. Accordingly when the description speaks about rolls of compliant material,'such composite rolls are understood to be included.

As the toned substrate ll, 13 passes between the rolls l5 and 17, the surface of the compliant roll 17 apparently becomes slightly distorted, as seen in exaggerated representation at 19 in FIG. 2, so that pressure is distributed over a wider part of the substrate. More'- over, the more compliant characteristic of the roll 17 makes is possible for the roll to adjust to variations in the thickness of thepaper substrate or the toner deposit, and thereby distribute the pressure more evenly, making it possible to effect application of a substantially uniform pressure to areas containing the toner image which is to be fixed. It is possible that in passing between the rolls, some shear is developed which contributes. to the fusing of the toner to the paper. However, it is believed that the application of a uniform pressure to the toner is probably the primary factor in the achievement of good toner fixing. l

In passing the toner bearing substrate into the nip of rolls 15 and 17, it is desirable that the toned side be broughtinto contact with the relatively rigid roll 15. This results in better pressure fixing to the substrate surface and in the prevention of toner build-up on the more compliant roll surface. This latter factor is particularly important where the surface of the more compliant rol] possesses any degree of porosity, for the finely divided toner could gradually build up in the surface pores. The relatively rigid roll is preferably of a material whose surface is smooth and non-porous, and which has the property of resisting adhesive attachment for the resins employed in the toner particles. Chrome plated steel is generally quite effective for this purpose. When the toned surface is faced towards the relatively rigid roll as described above, the substrate must, of course, be of a rather flexible nature to permit the action of the more compliant roll to have its desired effect.

In the drawing, the compliant roll 17 is shown as having a larger diameter than the relatively rigid roll. This is normally desirable but not necessary. Whether the two rolls are 'ofthe same or different size, they are rotated so as to have essentially the same surface speed.

This means that the shear developed, if any, will be due almost solely to the surface characteristics of the more compliant roll.

The loading to be applied to the rolls or pressure members 15 and 17 may be effected by joint loading and driving means of conventional character indicated diagrammatically at 21 in FIG. 1, and varies with a number of factors such as the resilience of the members and the pressure response level of the toner. The initial tests conducted in connection with this discovery were performed using a cotton filled roller of a hardness on the Shore-D scale of about and having a calculated modulus of elastic in compression of about 200,000

p.s.i. operating against a steel-roller. It was found that many conventional toners were effectively fixed to the substrate when the loading was in the range of about 200 pounds to 400 pounds per lineal inch. The toners used in these tests were conventional dry toners embodying as the binding agent the resins customarily used heretofore for this purpose. A calculation of the peak pressure which the rollers could be said to apply, on an average, at the incremental'area of, their contact gives about 5,000 to 10,000 p.s.i. v

These figures represent a particular example of a rather usual situation in which the invention can be applied, but it will be understood that the loading of the pressure members can be'adjusted to give the desired pressure, depending upon the rigidity of the roll material used, and that the pressure may be varied substantially to meet the fixing requirements of the particular toner.

Other tests were conducted using a nylon roller in place of the cotton filled roller, and then using a second nylon roller in place of the steel roller, to provide two relatively compliant rollers operating against each other. For purposes of calculations, the modulus of elasticity in compression for the nylon rollers were deemed to be 400,000 p.s.i. based on the manufacturrollers to about 3,000 p.s.i. for the same toners fixed between one steel and one nylon roller; and from about 3,800 p.s.i. for moderately soft toners fixed between two nylon rollers to about 5,300 p.s.i. for the same toners fixed between one steel and one nylon roller.

Absolute peak nip pressure values it should be noted are not delim itative of the scope of'the invention. However, it may be helpful to point out for the. purpose of general understanding of the background ofthe inven 'tion that values within the range of about 2,000 p.s.i.

to 10,000 p.s.i., are the ones which would be more frequently. encountered in the practice of the invention. Based on the complete discussion presented herein, it will be apparent to those acquainted with the art that the inventive. 'conceptinvolves the use of one or more compliant rollers to apply the requisite fixing pressure as opposed to mating hard-surfaced rollers as was heretofore thought to be essential. Specifically, even if an effective toner having a threshold pressure equivalent to 1,000 p.s.i. peak at the roller nip, or less, was available, the novel concept of using at least one compliant roller to provide heatless fixing would still provide the key to success if the system exhibits the appropriate 'deflection at the pressures used and discussed in detail hereinafter.

While the particular resilient rollers described above had calculated moduli of elasticity within the range of about 200,000-450,000 p.s.i., it will be understood that other resilient materials can be used in applying the invention and having a modulus much higher than 450,000 p.s.i. based on principles to be explained hereinafter. As to the minimum modulus, it should be such that the material does not deform'excessively. Usually lus of the more compliant roll will usually be found to be about 2,000,000 p.s.i.

As a basis for comparison it may be noted that the modulus of elasticity for steels is close to 30,000,000

p.s.i.

The immediately foregoing statements will perhaps be more readily understood in the light of the following comments.

6 Strain (Fourth Edition), by Raymond J. Roark, pub- -lished by McGraw-l-lill Book Company.

The mechanical interaction of two parallel cylinders urged against one another has been extensively investierted by the cylinders at the nip. An example of these relationships can be found in Formulas for Stress and On page 320 of the Roark text, table XIV,- Section 5, is found the expression: b 1.6 p D; D /(D,+D 1 1 1 2 2 where:

contact area under load (See FIG. 3); p represents the cylinder loading in pounds per lineal inch; D, and D represent the diameters of the cylinders in inches; v V and V represent Poissons ratio in compression for the materials of the cylinders; and E and E represent the modulus of elasticityin compression for the materials of the cylinders, stated in pounds per square inch.

From this it will be seen that when a measurement is taken of the quantity B (as by loading the rolls with a pressure transfer material and a copy'sheet therebe tween and measuring the breadth of the print) and if one of the rolls has an E of known value (such as steel), the E (calculated modulus of elasticity) for the-other roll can be readily obtained (The effective value of Poissons ratio for materials in the usable range may be assumed to be closely in the neighborhood of 0.3 in

case there is no value, reported in the literature, espe-. I

cially since this quantity has little effect on the calculated result).

At the same point in the text identified above, there is also found the expressioni Where Max. s represents the maximum compressive stress or peak unit pressure effect at the nip, expressed in p.s.i., and the other symbols have the same significance as above. As will be readily seen, this formula gives the calculated peak nip pressure directly by merely substituting the appropriate values for p, D,, D E E and the reported or assumed values for Poissons ratio.

The significance of certain of the foregoing symbols will perha'psbe more clearly understood by reference toFIG. 3 which shows two cylinders which may be considered as corresponding to rolls l5 and 17 of FIGS. 1 and 2. In the full line position the cylinders are unloaded, and the'axis of cylinder 15 is at A'. Inthe dotted line position the cylinders are under an applied load p which causes the axes to move closer together as represented by the shift of the axis of 15m B. The distance AB or y can be measured and is referred to as the deformation. The loaded cylinders demonstrate a narrow band of contact under load having a width b which can be measured as heretofore described. Similarcalculations can be made if either member becomes a plane by letting the value for the diameter of that member approach infinity in the above expressions, in which case D D /D, D approaches D.

The tests conducted in connectionwith this invention have indicated that a certain calculated peak pressure of the toner material. As previously stated, for conventional toners currently in use. i.e., those requiring a cylinder loading of about 200to about 400'pounds per linear inch, a calculated peak pressure of at least 5,000

b represents the transaxial width in inches of the p.s.i. is needed to secure fixing while for very soft toners, peak nip pressures as low as about 2,000 p.s.i. surface. The fixing here contemplated involves essentially altering the state of the toner resin sufficiently to make it flow and adhere to itself and to the substrate. This is, presumptively, primarily due to a pressure-induced temperature rise with the toner material although mechanical action may play a minor role in the fixing action also. Toners requiring a lesser pressure have been developed and may be used in the practice of the present invention. Examples of soft toners, fixable with only nominal pressure are disclosed in Canadian Pat. No.

874,01 l issued July 6, 1971 to the assignee of the pres- Example I Ingredient Wt.

Hexanamide 46 Hydroxylated fatty acid 10 Paraffin wax 30 Nubian resin black 12 Carbon black pigment (Neo-spectra-Mark II) 2 Ingredient Wt.

Acrawax C Nubian Resin black Carbon black pigment mus.

Using the formula described above, a peak nip pressure was calculated to be 5313.6 p.s.i.

The level of fixing achieved was deemed to be excellent.

EXAMPLE IV I The procedure of Example III was repeated using the 3 Again, the level of fixing attained was deemed to be excellent.

Example. V Ingredient The above toner composition was prepared in accordance with procedure described in the aforesaid Canadian Pat. No. 874,811 and deposited in a predetermined pattern on a lithographic master. The toned master was then passed between a steel and a nylon roller set at a cylinder loading of 50 p.l.i.-Using the formula described above, a peaknip pressure was calculated to be 3,067.8 p.s.i. The level of fixing, as evaluated by'measuring the optical density of toner transferred from the masterto a cloth square utilizing a Crockmeter CM-S instrument (Atlas Electric Devices, Chicago, Illinois) was deemed to be very good.

The foregoing composition was processed as in Example I and the resulting tonerdeposited on a lithographic master, also as described in Example I. The level of fixing at a cylinder loading of 50 p.l.i. was deemed to be good.

v EXAMPLE lll The procedure of Example I was repeated with the following composition except that the cylinder loading was set at 150 p.l.i.:

. M w 5 No U30 U A toner having the above composition was deposited on Hammermill Xerocopy 10300-2 paper in accordance with predetermined pattern.

The toned sheet was then passed through a pressure fixing unit consisting of two nylon rollers operating against each other at a cylinder loading of 363 p.l,i; A peak nip pressure was calculated at 5,885 p.s.i. The level of fixing was deemed to be very good.

The parameters involved in securing adequate uniform fixing appear, from the tests so far conducted, to be substantially as describedhereinafter.

The materials for the purpose members or rolls are- (or where, as in the preferred example, one roll has significantly more give or compliance than the other, the material for the compliant member or roll is) selected to have values (or a value) of the modulus of elasticity such that, when a loading p is applied which generates a calculated peak nip pressure (Max. s equal to or slightly greater than the threshold pressure for the toner under consideration, there is generated a measured deformation (y) which is still within the elastic limit for the material and whose value is a substantial multiple of the average variation in the'workpie'ce iting characteristics, be neglectedin computing the thickness variation. It is contemplated, however, that situations involving very uniform substrates and toners exhibiting variations in particle size would respond equally to the methods and apparatus proposed herein, so that when a workpiece thickness variation is referred to hereinafter, this form will, be understood as included aswell as formed of workpiece variation arising primarily from substrate nonuniformity.

rolls will be of a material having a modulus of elasticity in compression such that, when subjected to a loading which develops a calculated peak nip pressure of at least-the threshold pressure of the toner in question,

For purposes of convenience, variations of this sort which appeaar as a result of thickness measurement tests may be referred to as thickness variations;"

The term substantial multiple, used in the immediately foregoing paragraph, means at leastseveral times, and in practical effect, ithas been found that, when the calculated peak pressure at the trip is at or slightly above the threshold pressure of the'toner, a multiplier of about five, as a minimum, should beapplied to the average variation to determine the appropriate deformation in order to secure reasonably uniform fixing on the surface of the subs'tratetA more generally perferred value would be a multiplier of 10.

This multiplier'does not have a'firmly fixed value or range, however, but probably depends to some extent on the amount'by which the calculated peak nip pressure used is permitted to exceed that required for the toner in question.

Thus, for a toner whose threshold pressure is 5,000 p.s.i., and having in mind an-ordinary paper sheet with an average thickness variation of about 0.0004 inches, the material of the roll 17 would be so selected as to its modulus of elasticitytE) that, when loaded to a value p which willgive the calculated peak nip pressure of 5,000 psi required, or a little more, the measured deformation y should be at least 5 X 0.0004 or 0.002 inches. As pointed out above, this might prove some what marginal, and the E would preferably be so selected that a deformation y of about 10 X 0.0004 or 0.004 inches can be achieved to insure absolute fixing uniformity. However, if we should use a loading p which would produce a calculated peak nip pressure rather greater than is needed for the toner in question, say 15,000 to 20,000 p,s.i., andif thiscould be used without damaging the substrate, then it is expected that the deformation generating multiple applied to the average variation could be permitted to have a lesser value, perhaps in the range of 3 to 4 as a minimum.

From the foregoing discussion it will be apparent that having the threshold pressure of .the toner in mind, and the average variation in workpiece properties (represented as a thickness variation)it is possible to determine readily whether any particular solid material of a coherent elastic nature will have the properties needed to form an effective pressure fixing member. For convenience it may be stated that the pressure members or they will exhibit a deformation which is a substantial multiple of the workpiece thickness variation.

it will be understood that, while the two roll form has been shown and described, either pressure member may be formed as a platen withthe other having a roll or segment configuration and being in rolling pressure contact therewith.

Most of the powdered toners now commonly known and used may be used in forming copies by the process of this invention, However, since the method of this'invention achieves uniform toner adherence to the substrate surface by applicationjof pressure alone, it pres- I ents an opportunity to use other finely divided powders for toners which are not necessarily the same as those usable in heat fusing. Thus, a greater flexibility in toner choice'and final copy characteristics is available.

The method of pressure fixing of this invention makes it possible to work with-wider substrate sheets than is possible with the use of two hard surface rolls. Past experience inusing two'hard surface rolls has indicated that problems of achieving satisfactory characteristics in the untoned surface areas; are materially increased as the width of the substrate is increased. This intensification of the fixing problem with increase in width is not experienced when fixing is effected in accordance with the procedure set out in the foregoing description. i i It will thus'be seen that the objects set forth above, among. those made apparent from the preceding description, are efficiently attained and since certain changes may be madeiin carrying .out the above method, without departing fromthe scope of the invention it is intended that allmatter contained in the 'above description shall be interrupted as illustrative and not in a limiting sense; i i

. While preferred embodiments of the invention have been described and illustrated, it is to be understood that these are capable of variation and modification. Accordingly, the aim in the appended claims is to cover all such variations and modifications as may fall within configuration under fthe electrical control of said charge pattern to create a workpiece having thickness variations; and fixing the toner powder image to said substrate, wherein the last mentioned step includes providing two unheated elastic pressure members which progressively contact each other along a narrowband defining a nip, said members possessing moduli of elasticity compression permitting, when said members are loaded sufficiently to provide a calculated peak nip pressure in excess of the threshold pressure for the toner, deformation at said nip in an amount corresponding to a substantial multiple of the thickness variation of said workpiece; and loading said pressure members to an extent providing a calculated peak nipv pressure in excess of said threshold pressure for the toner when said workpiece is disposed between said compression within the range of about 100,000 to about 2,000,000 p.s.i.

3. The method defined in claim 1 wherein each of said pressure members has a modulus of elasticity in compression within the range of about 100,000 to about 2,000,000 p.s.i.

4. The method defined in claim 1 wherein at least one of said pressure members'has a surfaceformed of nylon.

5. The method defined in claim 1 wherein one of said pressure members has a surface formed of steel which is disposed to contact said powder toner image when said workpiece is passed between said pressure members.

6. The'method defined in claim 1 wherein both of said pressure members have surfaces formed of nylon.

7. The method defined in claim 1 wherein one of said pressure members has'a surface formed of textile material.

8. The method defined in claim 1 wherein at least one of said pressure members is a roller.

9. The method defined in claim 1 wherein said pressure members are rollers.

10. The methodof fixing a toner image to a substrate which comprises passing the substrate with a powder toner image thereon under ambient temperature conditions between a pair ofunheated pressure members progressively contacting each other along a narrow band, at least one of said members being of a somewhat compliant material having a modulus of elasticity in compression within the range of about 100,000 to about 2,000,000 p.s.i., and applying to the pressure members a loading sufficient to provide a calculated peak nip pressure in excess of the toner threshold pressure and averaging at a value within the range of about 2,000 to about 10,000 p.s.i., for as long as the toner bearing portions of the substrate are in contact with a pressure member during the passage.

11. The method defined in claim wherein at least one of said pressure members has a surface formed of nylon.

12. The method defined in claim 10 wherein each of said pressure members has a surface formed of nylon.

13. The method defined in claim 10 wherein one of said pressure members has a surface formed of textile material. 14. The method defined in claim 10 wherein one of said pressure members has a chrome-plated steel surface which is disposed to'contact said powder toner image when said substrate is passed between said pressure members.

both of 15. The method defined in claim 10 wherein at least one of said pressure members is a roller.

16. The method defined in claim 10 wherein bothof said pressure members are rollers.

17. Apparatus for providing a permanent image on a substrate of substantial width, wherein-the image is a fixed powder image of electroscopic toner powder having a predetermined threshold pressure, comprising means for creating an electrostatic charge pattern in image configuration; means for depositing electroscopic toner powder upon said substrate to form an image pattern configuration under the electrical control of said charge pattern to create a workpiece having thickness variations; and means for fixing the toner powder image to said substrate, wherein the last mentioned means includes two unheated elastic pressure members which progressively contact each other'along a narrow band defining a nip and thereby advance a workpiece therebetween, said members possessing moduli of elasticity in compression permitting, when said members are loaded sufficiently to provide a calloading said pressure members to an extentproviding a calculated peak nip pressurein excess of said threshold pressure for the toner when said workpiece is disposed between said members. i

18. Apparatus for providinga permanent image on a substrate of substantial width wherein the image is a fixed powder, imageof electroscopic toner powder, comprising means for creating an'electrostatic charge pattern in image configuration; means for despositing electroscopic toner powder upon said substrate to form an image pattern configuration under the electrical control of said charge pattern; and means for fixingthe toner powder image to said substrate, wherein the last mentioned means includes a pair of unheated pressure members arranged for progressively contacting each other along a narrow band with rolling pressure contact, at least one of said members having amodulus of elasticity in compression within the range of from about 100,000 to about.2,000,000 p.s.i.; and means providing a load on said pressure members of such of said rollers has a surface formed of a textile material.

v V r Page 1 of UNITED STATES PATENT OFFICE two Pages "CERTIFICATE, 0F CORRECTION Patent v "3 854 975 p I Dated December 17, 1975 1 'Inventor (s)'Richard S. Brenneman, David W. Lovering, Frederick E. Barr,

It is certified that error appears in the above-identified patent l p and that said Letters Patent are hereby corrected as shown below:

Column l, line 8 (numbered 10) after the Word "powder" there should be inserted --image--. Ccplumn'Z, line 30, "or narrow" should read -of narroW--; the heading DESCRIPTION OF THE PREFERRED EMBODIMENT" I I appearing in lines 57 and 58 should instead appear between lines 39 and 40.

Column 3, line 12, "line of" should read --line or--; line 44, "!purpose'd" should read "purposesline 48, "must" should read --most--; line 52,

t a after "one-fourth" should be inserted --inch--; line 62, "makes is" should read --makes it", Column 4, line42, 'elastic" should-read "elasticity-- Column 6, the formula appearing in lines 4 and 5 should read:

lColulnn 6, the formula appearing in lines32 and 33 should read:

. Y n D1D2 Max. s 0079s a 1 v 1 v FoRfitPo-mmho-sm uscoMM-Dc 60376-P69 a u.s. sovnnmrur manna omc: lub e a 1:4

, t v Page 2 of Y V UNITEDSTATES PATENT OFFICE twifPages CERTIFICATE OF "CORRECTION P atent NoV- 3 854 975 I V December 17, 1975 3 IfiventoflS) Richard SQ Brenneman; David W. LQveringQFredrick E. Barr 1 It is certified that error appears in the above-identified patent and that said Letters Patent "are hereby corrected as shown below:

' Column 6, little 5 8 the fraction "D D lD D should read:

Colmxm 7, line 33 (numbered 36) "Pat. No. 874,811 should read -'--Pat. No. 874,9ll--;line 47 (numbered55) 'purp ose" should read "pressure". Column 9, line 13), after "characteristics," there should be i t d 1,1 1 m gnentj'fof the variation may, as a practical matter,-'- line '20, "formed" should read -"--hforms--. Claim" 1, line 15, following "elasticity" thereshould be inserted --*in--.

Signedfahd "sealed this, 13th day of May 1.97 5.

(SEAL) Attest: l v 1 C. MARSHALL DANN RUTH -C. MASON, Commissioner of Patents .Attesting Officer and Trademarks FORM PQ-105D (10-69) USCOMM-DC bean-Pen h i [1.5. GOVIINHENT PRINTING OFFICE IO, 0-36-l3l- Page 1 of UNITED STATES PATENT OFFICE I tWO Pages CERTIFICATE OF CORRECTION Patent 3 854 975 Dated December 17, 1975 Inventor (s)Richard S. Brenneman, David W. Levering, Frederick E. Barr It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 8 (numbered 10) after the word "powder" there should be inserted --image--. Column 2, line 30, "or narrow" should read -of narrow--; the heading DESCRIPTION OF THE 'PREFERRED EMBODIMENT" appearing in lines 57 and 58 should instead appear between lines 39 and 40. Column 3, line 12, "line of" should read --line or--; line 44, "purposed" should read --purposes--; line 48, "must" should read --most--; line 52, after "one-fourth" should be inserted --inch--; line 62, "makes is" should read --makes it--. Column 4, line 42, "elastic" should read "elasticity". Column 6, the formula appearing in lines 4 and 5 should read:

ORM PO-OSO (10-69) USCOMM-DC 6O376-P69 u.s. GOVERNMENT HUNTING omcz: Iss9 o-:6-sa4 Page 2 of UNITED STATES PATENT OFFICE two pages CERTIFICATE OF CORRECTION Patent No. 3 854 975 Dated December 17, 1975 Inventor-(S) Richard S. Brenneman, David W. Levering, Frederick E. Barr It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, line 58, the fraction "D D /D D should read:

DIDZ

Column 7, line 33 (numbered 36) "Pat. No. 874,811" should read --Pat. No. 874,911"; line 47 (numbered 55), "purpose" should read -pressure--. Column 9, line 13, after "characteristics," there should be inserted --this component of the variation may, as a practical matter,--; line 20, "formed" should read --forms--. Claim 1, line 15, following "elasticity" there should be inserted --in--.

Signed and sealed this 13th day of May 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer I and Trademarks PC4050 (169) USCOMM-DC 60376-P69 U.S. GOVERNMENT PRINTING OFFICE I I... O'-333l 

1. THE METHOD OF PROVIDING A PERMANENT IMAGE ON A SUBSTRATE OF SUBSTANTIAL WIDTH, WHEREIN THE IMAGE IS A FIXED POWDER IMAGE OF ELECTROSCOPIC TONER POWDER HAVING A PREDETERMINED THRESHOLD PRESSURE, COMPRISING THE STEPS OF CREATING AN ELECTROSTATIC CHARGE PATTERN IN IMAGE CONFIGURATE: DEPOSITING ELECTROSCOPIC TONER POWDER UPON SAID SUBSTRATE TO FORM AN IMAGE PATTER CONFIGURATION UNDER THE ELECTRICAL CONTROL OF SAID CHARGE PATTERN TO CREATE A WORKPIECE HAVING THICKNESS VARIATIONS; AND FIXING THE TONER POWDER IMAGE TO SAID SUBSTRATE, WHEREIN THE LST MENTIONED STEP INCLUDED PROVIDING TWO UNHEATED ELASTIC PRESSURE MEMBERS WHICH PROGRESSIVELY CONTACT EACH OTHER ALONG A NARROW BAND DEFINING A NIP, SAID MEMBERS POSSESSING MODULI OF ELASTICITY COKPRESSION PERMITTING, WHEN SAID MEMBERS ARE LOADED SUFFICIENTLY TO PROVIDE A CALCULATED PEAK NIP PRESSURE IN EXCESS OF THE THRESHOLD PRES-
 2. The method defined in claim 1 wherein at least one of said pressure members has a modulus of elasticity in compression within the range of about 100,000 to about 2,000,000 p.s.i.
 3. The method defined in claim 1 wherein each of said pressure members has a modulus of elasticity in compression within the range of about 100,000 to about 2,000,000 p.s.i.
 4. The method defined in claim 1 wherein at least one of said pressure members has a surface formed of nylon.
 5. The method defined in claim 1 wherein one of said pressure members has a surface formed of steel which is disposed to contact said powder toner image when said workpiece is passed between said pressure members.
 6. The method defined in claim 1 wherein both of said pressure members have surfaces formed of nylon.
 7. The method defined in claim 1 wherein one of said pressure members has a surface formed of textile material.
 8. The method defined in claim 1 wherein at least one of said pressure members is a roller.
 9. The method defined in claim 1 wherein both of said pressure members are rollers.
 10. The method of fixing a toner image to a substrate which comprises passing the substrate with a powder toner image thereon under ambient temperature conditions between a pair of unheated pressure members progressively contacting each other along a narrow band, at least one of said members being of a somewhat compliant material having a modulus of elasticity in compression within the range of about 100,000 to about 2,000,000 p.s.i., and applying to the pressure members a loading sufficient to provide a calculated peak nip pressure in excess of the toner threshold pressure and averaging at a value within the range of about 2,000 to about 10,000 p.s.i., for as long as the toner bearing portions of the substrate are in contact with a pressure member during the passage.
 11. The method defined in claim 10 wherein at least one of said pressure members has a surface formed of nylon.
 12. The method defined in claim 10 wherein each of said pressure members has a surface formed of nylon.
 13. The method defined in claim 10 wherein one of said pressure members has a surface formed of textile material.
 14. The method defined in claim 10 wherein one of said pressure members has a chrome-plated steel surface which is disposed to contact said powder toner image when said substrate is passed between said pressure members.
 15. The method defined in claim 10 wherein at least one of said pressure members is a roller.
 16. The method defined in claim 10 wherein both of said pressure members are rollers.
 17. Apparatus for providing a permanent image on a substrate of substantial width, wherein the image is a fixed powder image of electroscopic toner powder having a predetermined threshold pressure, comprising means for creating an electrostatic charge pattern in image configuration; means for depositing electroscopic toner powder upon said substrate to form an image pattern configuration under the electrical control of said charge pattern to create a workpiece having thickness variations; and means for fixing the toner powder image to said substrate, wherein the last mentioned means includes two unheated elastic pressure members which progressively contact each other along a narrow band defining a nip and thereby advance a workpiece therebetween, said members possessing moduli of elasticity in compression permitting, when said members are loaded sufficiently to provide a calculated peak nip pressure in excess of the threshold pressure for the toner, deformation at said nip in an amount corresponding to a substantial multiple of the thickness variation of said workpiece; and means for loading said pressure members to an extent providing a calculated peak nip pressure in excess of said threshold pressure for the toner when said workpiece is disposed between said members.
 18. Apparatus for providing a permanent image on a substrate of substantial width wherein the image is a fixed powder image of electroscopic toner powder, comprising means for creating an electrostatic charge pattern in image configuration; means for dEspositing electroscopic toner powder upon said substrate to form an image pattern configuration under the electrical control of said charge pattern; and means for fixing the toner powder image to said substrate, wherein the last mentioned means includes a pair of unheated pressure members arranged for progressively contacting each other along a narrow band with rolling pressure contact, at least one of said members having a modulus of elasticity in compression within the range of from about 100,000 to about 2,000,000 p.s.i.; and means providing a load on said pressure members of such magnitude that there is exerted on the substrate passing therebetween a calculated pressure on the imaged substrate at the peak pressure point on its passage through the machine having an average value within the range of from about 2,000 to about 10,000 p.s.i.
 19. The apparatus defined in claim 18 wherein both of said pressure members are rollers.
 20. The apparatus defined in claim 19 wherein at least one of said rollers has a surface formed of nylon.
 21. The apparatus defined in claim 19 wherein one of said rollers has a surface formed of a textile material. 